/// <summary>
 /// 扫描服务
 /// </summary>
 public interface IServerScanner
 {
 /// <summary>
 /// 扫描完成
 /// </summary>
 event EventHandler<List<ConnectionResult OnScanComplete;
 /// <summary>
 /// 报告扫描进度
 /// </summary>
 event EventHandler<ScanProgressEventArgs> OnScanProgressChanged;
 /// <summary>
 /// 扫描端口
 /// </summary>
 int ScanPort { get; set; }
 /// <summary>
 /// 单次连接超时时长
 /// </summary>
 TimeSpan Timeout { get; set; }
 /// <summary>
 /// 返回指定的IP与端口是否能够连接上
 /// </summary>
 /// <param name="ipAddress"></param>
 /// <param name="port"></param>
 /// <returns></returns>
 bool IsConnected(IPAddress ipAddress, int port);
 /// <summary>
 /// 返回指定的IP与端口是否能够连接上
 /// </summary>
 /// <param name="ip"></param>
 /// <param name="port"></param>
 /// <returns></returns>
 bool IsConnected(string ip, int port);
 /// <summary>
 /// 开始扫描
 /// </summary>
 void StartScan();
 }

/// <summary>
 /// 扫描结果
 /// </summary>
 public class ConnectionResult
 {
 /// <summary>
 /// IPAddress 地址
 /// </summary>
 public IPAddress Address { get; set; }
 /// <summary>
 /// 是否可连接上
 /// </summary>
 public bool CanConnected { get; set; }
 }
 /// <summary>
 /// 扫描完成事件参数
 /// </summary>
 public class ScanCompleteEventArgs
 {
 /// <summary>
 /// 结果集合
 /// </summary>
 public List<ConnectionResult> Reslut { get; set; }
 }
 /// <summary>
 /// 扫描进度事件参数
 /// </summary>
 public class ScanProgressEventArgs
 {
 /// <summary>
 /// 进度百分比
 /// </summary>
 public int Percent { get; set; }
 }
 /// <summary>
 /// 扫描局域网中的服务
 /// </summary>
 public class ServerScanner : IServerScanner
 {
 /// <summary>
 /// 同一网段内 IP 地址的数量
 /// </summary>
 private const int SegmentIpMaxCount = 255;
 private DateTimeOffset _endTime;
 private object _locker = new object();
 private SynchronizationContext _originalContext = SynchronizationContext.Current;
 private List<ConnectionResult> _resultList = new List<ConnectionResult>();
 private DateTimeOffset _startTime;
 /// <summary>
 /// 记录调用/完成委托的数量
 /// </summary>
 private int _totalCount = 0;
 public ServerScanner()
 {
  Timeout = TimeSpan.FromSeconds(2);
 }
 /// <summary>
 /// 当扫描完成时，触发此事件
 /// </summary>
 public event EventHandler<List<ConnectionResult OnScanComplete;
 /// <summary>
 /// 当扫描进度发生更改时，触发此事件
 /// </summary>
 public event EventHandler<ScanProgressEventArgs> OnScanProgressChanged;
 /// <summary>
 /// 扫描端口
 /// </summary>
 public int ScanPort { get; set; }
 /// <summary>
 /// 单次请求的超时时长，默认为2秒
 /// </summary>
 public TimeSpan Timeout { get; set; }
 /// <summary>
 /// 使用 TcpClient 测试是否可以连上指定的 IP 与 Port
 /// </summary>
 /// <param name="ipAddress"></param>
 /// <param name="port"></param>
 /// <returns></returns>
 public bool IsConnected(IPAddress ipAddress, int port)
 {
  var result = TestConnection(ipAddress, port);
  return result.CanConnected;
 }
 /// <summary>
 /// 使用 TcpClient 测试是否可以连上指定的 IP 与 Port
 /// </summary>
 /// <param name="ip"></param>
 /// <param name="port"></param>
 /// <returns></returns>
 public bool IsConnected(string ip, int port)
 {
  IPAddress ipAddress;
  if (IPAddress.TryParse(ip, out ipAddress))
  {
  return IsConnected(ipAddress, port);
  }
  else
  {
  throw new ArgumentException("IP 地址格式不正确");
  }
 }
 /// <summary>
 /// 开始扫描当前网段
 /// </summary>
 public void StartScan()
 {
  if (ScanPort == 0)
  {
  throw new InvalidOperationException("必须指定扫描的端口 ScanPort");
  }
  // 清除可能存在的数据
  _resultList.Clear();
  _totalCount = 0;
  _startTime = DateTimeOffset.Now;
  // 得到本网段的 IP
  var ipList = GetAllRemoteIPList();
  // 生成委托列表
  List<Func<IPAddress, int, ConnectionResult funcs = new List<Func<IPAddress, int, ConnectionResult();
  for (int i = 0; i < SegmentIpMaxCount; i++)
  {
  var tmpF = new Func<IPAddress, int, ConnectionResult>(TestConnection);
  funcs.Add(tmpF);
  }
  // 异步调用每个委托
  for (int i = 0; i < SegmentIpMaxCount; i++)
  {
  funcs[i].BeginInvoke(ipList[i], ScanPort, OnComplete, funcs[i]);
  _totalCount += 1;
  }
 }
 /// <summary>
 /// 得到本网段的所有 IP
 /// </summary>
 /// <returns></returns>
 private List<IPAddress> GetAllRemoteIPList()
 {
  var localName = Dns.GetHostName();
  var localIPEntry = Dns.GetHostEntry(localName);
  List<IPAddress> ipList = new List<IPAddress>();
  IPAddress localInterIP = localIPEntry.AddressList.FirstOrDefault(m => m.AddressFamily == AddressFamily.InterNetwork);
  if (localInterIP == null)
  {
  throw new InvalidOperationException("当前计算机不存在内网 IP");
  }
  var localInterIPBytes = localInterIP.GetAddressBytes();
  for (int i = 1; i <= SegmentIpMaxCount; i++)
  {
  // 对末位进行替换
  localInterIPBytes[3] = (byte)i;
  ipList.Add(new IPAddress(localInterIPBytes));
  }
  return ipList;
 }
 private void OnComplete(IAsyncResult ar)
 {
  var state = ar.AsyncState as Func<IPAddress, int, ConnectionResult>;
  var result = state.EndInvoke(ar);
  lock (_locker)
  {
  // 添加到结果中
  _resultList.Add(result);
  // 报告进度
  _totalCount -= 1;
  var percent = (SegmentIpMaxCount - _totalCount) * 100 / SegmentIpMaxCount;
  if (SynchronizationContext.Current == _originalContext)
  {
   OnScanProgressChanged"Compete");
   _endTime = DateTimeOffset.Now;
   Debug.WriteLine($"Duration: {_endTime - _startTime}");
  }
  }
 }
 /// <summary>
 /// 测试是否可以连接到
 /// </summary>
 /// <param name="address"></param>
 /// <param name="port"></param>
 /// <returns></returns>
 private ConnectionResult TestConnection(IPAddress address, int port)
 {
  TcpClient c = new TcpClient();
  ConnectionResult result = new ConnectionResult();
  result.Address = address;
  using (TcpClient tcp = new TcpClient())
  {
  IAsyncResult ar = tcp.BeginConnect(address, port, null, null);
  WaitHandle wh = ar.AsyncWaitHandle;
  try
  {
   if (!ar.AsyncWaitHandle.WaitOne(Timeout, false))
   {
   tcp.Close();
   }
   else
   {
   tcp.EndConnect(ar);
   result.CanConnected = true;
   }
  }
  catch
  {
  }
  finally
  {
   wh.Close();
  }
  }
  return result;
 }
 }
ServerScanner

private void View_Loaded()
  {
   // 在界面 Load 事件中添加以下代码
   ServerScanner.OnScanComplete += ServerScanner_OnScanComplete;
   ServerScanner.OnScanProgressChanged += ServerScanner_OnScanProgressChanged;
   // 扫描的端口号
   ServerScanner.ScanPort = 7890;
  }
  private void StartScan()
  {
   // 开始扫描
   ServerScanner.StartScan();
  }

  private void ServerScanner_OnScanComplete(object sender, List<ConnectionResult> e)
  {
   ...
  }
  private void ServerScanner_OnScanProgressChanged(object sender, ScanProgressEventArgs e)
  {
   ...
  }